AOS midterm Flashcards
define: concentration
number of molecules of a substance per unit volume
C = N/V
the amount of pollutant in a given volume of air
how much stuff is mixed in some mixture of many materials
convert 0 C to Kelvin
273K
convert -273 C to K
0 K
units of the SI system
m, kg, s, K/C
what is the current meter standard?
distance traveled by light in a vacuum in a known fraction of a second
what is the density of water?
1 kg/L
how does the atomic clock time standard work?
the oscillation period between two ground state levels in a cesium atom
what is mixing ratio?
ratio between the amount of the pollutant vs the amount of other gasses
(amount of one substance) / (amount of all the other substances)
what are the concentration units for gasses?
molecules per unit volume (mol./cm3)
what are the concentration units for particles?
mass per unit volume (micrograms/cm3)
effect of a change in volume on mixing ratio
no change; just spreading the particles out, not changing the numbers of particles
effect of a change in volume on concentration
concentration depends on volume
increase in V, decrease in C
decrease in V, increase in C
what is the steady-state-box model?
representation of environment as a ‘box’ and measuring inflow and outflow based on that volume
it is in ‘steady state’ when the concentration (and total amount) is not changing
what is a ‘source?’
everything that introduces pollutants into the air in the box
e.g. direct emission (by cars); transport by wind; chemical transformation; re-suspension (pollutant becoming free from liquid or or solid surface and become airborne)
what is a ‘sink?’
processes that remove or convert pollutants
e.g. ventilation (wind blows them away); chemical conversion; deposition (pollutant deposited to ground)
what is a ‘rate?’
quantification of how fast something is happening
rate of emission/loss (S/L)
S/L = (amount emitted or lost in time interval t) / (time interval t)
how to calculate the amount of material in the volume of space
source rate - sink rate = S - L
box model equation (steady state concentration of pollutant), q
q = (S or L)*tau / V
what percentage of earth’s surface is water?
70%
where did life first develop and why?
the oceans because the water protected from harmful UV rays
how did the earliest life forms get their energy?
they were heterotrophic - used organic molecules and broke them down to harvest the energy (fermentation)
why didn’t heterotrophy last?
these organic compounds were not abundant enough and supplies ran low quickly
what solved the organic carbon scarcity problem?
autotrophy - harvesting energy from inorganic substances in their environment
what is photosynthesis?
an autotrophic process that permitted the organisms to harvest energy from the sun - oxygenic and anoxygenic
what was the early type of photosynthesis?
anoxygenic - produced organic matter but did not produce molecular oxygen as a byproduct; used sulfur compounds
what was the most important evolutionary step and why?
evolution of oxygenic photosynthesis
oxygen started to accumulate in the environment
oxidized substances in the Earth’s crust
oxygenated the oceans
accumulated in the atmosphere, and absorbed the shortest wavelengths of solar ultraviolet radiation
led to formation of ozone gas from the oxygen
formation of the ozone layer and the Earth’s stratosphere
aided the absorption of solar UV radiation and eventually allowed life to evolve on dry land, outside of the oceans
changes to the Earth environment from this oxygenation due to photosynthesis
removes CO2 and adds O2; atmospheric CO2 decreases over time –> long, slow, cooling of the earth; too much oxygen for current anaerobic organisms, so they die off; ozone layer forms, allowing more diverse life forms to develop
how does ozone absorb UV radiation?
O3 + hv –> O2 + O
where hv is the energy of a photon of light
how is ozone formed?
illuminating oxygen w UV radiation
O2 + hv –> O + O
O + O2 + M –> O3 + M
what is the largest mass extinction ever and how much of the population was lost?
Permian Triassic mass extinction (PT event); loss of 60% of species
how did early humans impact the environment?
agriculture (cultivation of land, burning of wood, animal waste), heating (open wood fires indoors and burning of coal), and manufacturing (copper/bronze metals and leather tanning) altered the landscape and/or polluted the air with combustion of organic materials
what was the environmental impact of deforestation?
reduces a local sink for carbon dioxide
difference between pre-industrial society’s impacts on the environment and today’s impacts
pre: impacts were locally restricted; total world population was small; energy use was limited because it was based on renewable energy
calculate total pollution produced
C x r x Ap
C = population size [persons]
r = per capita resource consumption [resource units/person]
ap = pollution per resource unit consumed [pollt. units/res.units]
IPCC scenarios of population growth criteria
globalization vs local development (1 vs 2)
economic vs environmental emphasis (A vs B)
IPCC A1 marker scenario
globalization with economic emphasis –> rapid convergent growth (second smallest future population)
IPCC A2 marker scenario
local development with economic emphasis –> fragmented world (largest future population)
IPCC B1 marker scenario
globalization with environmental emphasis –> convergence with global environmental emphasis (smallest future population)
IPCC B2 marker scenario
local development with environmental emphasis –> local sustainability (second largest future population)
what drives the rise in atmospheric CO2
the burning of fossil fuels mainly with contributions from deforestation and other types of land use change
define weather
state of the atmosphere as we experience it instantaneously
define climate
average weather over an extended period of time in a specific region
define global climate
globally averaged weather over an extended period of time
define global average temperature
stable parameter for climate
how can we study past climates?
ice cores - snow layers with chemical indicators of past climates
how quickly can the climate change?
as quickly as 10 years
what is firn?
snow over 1 year old
what is a hoar layer?
a weak layer of frost that forms on the snow during calm, clear, and humid conditions
how deep do you have to go to get ice cores?
2m+
what do ice records tell us about past climates?
CO2 mixing ratios
relative temperature by the ratio of hydrogen and deuterium
strong covariance of atmospheric CO2 and temperature
what are earth’s permanent gasses and at what percent?
nitrogen (78%), oxygen (20%), argon (1%), and trace gasses
what are earth’s variable gasses?
water vapor (1) and carbon dioxide (2)
layers of the atmopshere (ground up)
troposphere, stratosphere, ozone layer, mesosphere, ionosphere (aurora)
what is the kind of rate of change of pressure with altitude?
exponential
how do pressure and density and altitude mathematically relate?
pressure and density both decrease by a half for every 5.5 km increase in altitude
what is boyle’s law
P1V1 = P2V2 (inverse relationship)
what is adiabatic expansion?
lower parcel temperature as parcel rises in atmosphere and expands
how much does the greenhouse effect raise overall temp by?
33K
what is thermal energy?
how hot a body is; more the hotter it is (higher temp)
what is radiative energy?
light carries energy
what is chemical energy?
molecules can store energy
what is the suns surface called?
the photosphere
what is the temperature at the photosphere?
~6000K
how does the sun generate energy?
nuclear fusion 2H —> He + (thermal) energy
what is a black body?
a perfect blackbody absorbs all wavelengths of electromagnetic radiation (emr) that fall on it
what is kirchoff’s law?
a blackbody also emits all wavelengths of emr
what happens to a blackbody at a lower temp and example
less radiation is emitted and color becomes redder
incandescent lamps behave like black bodies
what happens to a blackbody at a higher temp
peaks at shorter wavelengths and more energy is emitted overall
what is albedo
percentage radiation reflected on earth
what is the average surface temp of earth without an atmosphere
255K
what happens to the radiation that reaches earth
UV absorbed by O2 and O3; IR is absorbed by CO2 and H2O except for a small atmospheric window that lets some of earths IR out; most visible light is not absorbed
what is the greenhouse effect?
upgoing IR is absorbed and emitted back to the ground thus heating the earth more with the radiation
how much of earth’s surface is covered in clouds?
about half at any given time
name 2 types of clouds
cumulus and cirrus
effect of high clouds on earth;s albedo
high clouds have a low albedo so do not affect solar radiation in a major way
greenhouse effect => weak
oevrall warming
effect of low clouds on earth’s albedo
high albedo of low clouds significantly reduce solar radiation reaching earth’s surface
greenhouse effect => warming not as strong as cooling effect from albedo
overall planetary cooling
what is the influence of aerosols/haze on the atmosphere?
similar to cooling by clouds
increases albedo —> cooling effect
signs of climate change
temperature change
change in cloudiness and rainfall
changes of arctic sea ice, ice caps, and glaciers
variation of sea level
climate change from natural causes
sunspot cycles; milankovitch cycles; volcanic eruptions
how do sunspot cycles effect climate change?
the suns emissions vary slightly in an 11 year period but the intensity is too weak to actually be noticed
how do milankovitch cycles affect climate change?
variations in earth’s orbit with periods of 22000 41000 and 100 000 yrs and could have been triggers for ice ages but magnitude is too small to explain current changes
how do volcanoes affect climate change?
ash and other particles block sunlight (albedo) => surface cools down
greenhouse gasses and primary sources
water vapor (no main source), CO2 (fossil fuel combustion), methane food production – rice and cows), N2O (agricultural - fertilized - soils), CFCs (refrigerants and industry)
How can aerosol (haze) impact the climate?
White aerosol can lead to cooling of the surface
Black aerosol can warm the atmosphere
how do we know climate change is real?
average land-surface air temp rose 1.3C; sea level has risen over the past 200 yrs; global glacier retreat; arctic sea ice retreat
best and worst scenarios for future climate change
best: we actively and effectively reduce emissions, temp will increase 1 degree celcius by the end of the century and then slowly decrease
worst: little reduction in greenhouse emissions, temp will increase 4 C by 2100 and 8 C by 2300
what is negative feedback
cause –> effect –> suppress
the effect suppresses the cause, decreasing the effect
positive feedback
increases the effect - self-sustaining
what is geoengineering and what are the 2 methods
manipulation of the earth’s climate system to counteract the effects of climate change caused by greenhosue gas emissions [last resort]
eg.
remove atmospheric carbon dioxide or reduce emissions via carbon sequestration (CDR)
manage solar radiation reaching earth’s surface (SRM)
alternative sources of energy
geothermal energy hydroelectric power nuclear energy biofuels wind energy solar radiation photovoltaics (solar cells)
what is CDR
carbon dioxide removal (cdr) - remove CO2 from atmosphere and store underground
what is srm
solar radiation management (srm) - reduce sunlight reaching earth’s surface
methods of CDR
reforestation, biochar, enhancement of natural weathering processes, enhancement of oceanic uptake of CO2, direct engineered capture of CO2,
methods of srm
increase surface reflectivity,
when was the ozone hole discovered?
1986
where can most ozone be found?
stratosphere
difference between good ozone and bad ozone
good is in stratosphere bad is below and considered smog
what is the chapman cycle
the conversion of oxygen to ozone and back again
chemical mechanism for the source of ozone in the chapman cycle
O2 + hv —> O + O
2x O + O2 —> O3
net: 3O2 —> 2O3
chemical mechanism for the sink of ozone in the chapman cycle – photolysis
O3 + hv —> O2 + O
O + O3 —> O2 + O2
net: 2 O3 —> 3O2
catalytic chemical mechanism for ozone destruction
O3 + X —> XO + O2
XO + O3 —> X + 2O2
net: 2O3 —> 3O2
natural catalysts for ozone destruction
NO, OH, Cl, Br
what is a vertical ozone column (TOC)
all the ozone in the column of 1 cm2 cross-section from the ground to space
classes of UV radiation and effects
A - lowest energy, not absorbed by ozone, doesn’t cause sunburn but can contribute to skin cancer; B - most absorbed by ozone layer, can cause sunburn and skin cancers; and C - most energetic, hazardous, used for sterilization, but is completely absorbed by the ozone layer
types of skin cancers
basal cell carcinomas; squanous cell carcinomas; melanoma
what are CFCs chemically
organic molecules where the H atoms have been completely replaced by F and Cl (completely artificial); very unreactive and chemicall stable and not harmful to humans, so seem like a good idea for aerosols but because they are unreactive, nothing removes them
timeline of the ozone hole over antarctica
May: sunset cooling; June: polar vortex; aug/sept/oct: sunrise, ozone hole develops; Nov.: polar vortex break-up
ozone hole appears in august
ozone hole max in september
ozone hole starts to fade in late october/early november
what is the polar vortex and some effects
wind circulation around antarctica in the stratosphere
inhibits air exchange with lower latitudes (air is trapped)
air in vortex cools down by thermal radiation
ozone depleted air can not be replensished
what are polar stratospheric clouds - PSCs
clouds of ice particles in 15-25 km altitude
what are psc types 1s made of
frozen nitric acid on a sulfuric acid core
what are psc type 2s made of
ice frozen onto nitric acid cores (frozen onto PSC type 1s)
what do pscs do to the air chemistry
convert reservoir to active species by heterogeneous reactions and removal of NO2
what is the molina cycle
a catalytic ozone destruction cycle with Cl as the catalyst that becomes important only with high levels of chlorine
name the active and reservoir species of Cl
HCl = Reservoir ClONO2 = Reservoir Cl = Active ClO = Active
What is exposure time in reference to pollutants?
Amount of time a person is exposed to pollutants
What is exposure time in reference to pollutants?
Amount of time a person is exposed to pollutants
What is acute exposure?
Large exposure dose that persists for a short time
What is chronic exposure?
Small exposure over a long period of time
How to calculate dose of pollutant a person recieved
Dose = C x Re x te x f Concentration Rate of intake Time exposed Fraction of pollutant retained in body
What is D50 in terms of pollutant doses
A dose where half the population experiences symptoms
How many premature deaths is it estimated that indoor air pollution causes?
3.3 million
What shape is a dose-response curve?
Somewhat s shaped
What is a binary response curve
On/off , when exposed to a certain amount everyone has symtoms and when less than that no one has symtoms
What does a linear response mean?
No zero risk dose
Types of toxicological studies
Clinical/lab experiments and epidemiological studies
Advantages of toxicological studies
Exposure to toxins is controlled and varied and controlled environment for subjects
Disadvantages of toxicological studies
Small sample and forced to extrapolate
Short experiment period (can’t truly measure chronic effects)
Subjects not usually human
What is an epidemiological study?
A statistical evaluation of historical records of actual human exposure
Advantages of epidemiological studies
Large sample size, long term studies of chronic effects
Lab costs/morality issues not an issue
Disadvantages of epidemiological studies
Lack of control of exposure and environment
Unknown history and behavior of subjects
More subjective
4 step risk assessment process
Hazard identification
Exposure assessment
Dose response assessment
Risk characterization
Main ways air pollutants are taken up
Skin, eyes, respiratory system
What is the first part of body to be exposed to pollutants
Skin and eyes
What are the 2 major regions of the respiratory system and what is in each?
Upper - nasal passages, larynx, trachea
Lower - bronchiol tubes and alveoli
How far do small particles get?
Down windpipe/trachea and to brionchial tubes –> bronchioli –> alveoli
What are blood poisons
Substances that are dangerous when taken up by the circulatory system
What are lachrymators
Gases such as ozone and sulfur dioxide which can irritate and ultimately damage the respiratory tract – esp alveoli
What happens to particles between 10 and 2 micro meters
Mainl deposited in mouth/nose/larynx region and 10-80% are retained
What happens to particles between 0.1-2 micro meters
Deposited in lung and small particles reach the alveoli and about 20% are retained
What happens physiologically with CO exposure
CO attaches to hemoglobin instead of oxygen and decreases oxygen carrying capacity of blood until the damaged red blood cells die off and new ones replace them
What happens upon uptake of SO2
Forma H2SO4 which can eat into lung tissue
What happens upon uptake of ozone
Strong oxidant and can eat into lung tissue but not as bad as SO2
Path of pollutants through human respiratory system
- Turbinates
- Larynx
- Trachea
- Bronchial tubes
- Bronchioles
- Alveolis
When do people die from CO exposure
After many hours at 600 ppmv
Normal ratios of CO
Less than 10 ppmv
what does asbestos do when it ages that causes health problems?
shreds into fine fibers that get lodged in the lungs
why was asbestos used frequently in the past?
for brake linings and insulation because heat doesn’t break it down
what is asbestosis?
the result of scar tissue encapsulating the trapped asbestos particles
what is plumbism
a lead induced disease leading to paralysis, loss of nerve function, and more
what rate do particles fall relative to size?
small particles fall slower and large particles fall faster - small particles stay in the air longer
why are children in more danger from particulates than adults?
they inhale more air per unit bodyweight
how do toxic compounds cause death
interfere with physiological functions
what do mutagens/carcinogens do?
cause mutation of dna or introduce tumors, but not all mutations result in a cancerous tumor
what do promutagens do?
cause indirect effects that form another mutagen in the body
how do we find out if a pollutant can cause cancer
not by animal toxicological studies because they are too expensive and take too long so we use salmonella bacteria and follow their mutation upon exposure to the pollutant
why is radon gas considered a carcinogen?
emits radioactive decay
carbon 14 dating?
carbon 14 slowly loses neutrons and transforms into C-12; the ration of C14/C12 can give age of object (lower ratio = older)
types of radioactive decay
alpha
beta
gamma
alpha decay
emits large, high energy alpha particle (He nuclei) that turns it into a progeny species and is easily blocked by paper and clothing
beta decay
emits a high energy electron which turns it into a new element and is smaller than an alpha particle so it takes reeeally thick clothing to stop it
gamma decay
emits a high energy photon with a really short wavelength that can penetrate a lot of things
what does radon 222 originate from
uranium 238
half life of uranium 238 and % remaining from earth’s formation
4.5 billion yr half life with 50% remaining from formation of earth
progeny of uranium 238
radon 226
progeny of radon 226
radon 222
half life of radon 222
4 days
where does radon 222 come from
seeps out of ground and contributes to background radiation
progeny of radon 222
polonium 214, bismuth, and lead isotopes
how does radon 222 get into body
attaches to particles which can be deposited in lung
how does radon get into the home
enters from ground through foundation and sometimes is sucked in by pressure changes caused by heating/cooling
health effects of radon
attached to particles and gets deposited in lungs where it decays further and can destroy lung tissue and cause lung cancer
what level of radon indoors is considered unsafe
over 4 pico curies per liter
types of pollution sources
point source, area source, line source
point source of pollution
localized source that spreads out; e.g. smoke stack or car tailpipe
area pollution source
source covers a wide area and we just need to see the cluster of point sources aggregate rather than each individual source
line source of pollution
point sources that move along a line e.g. highway
types of transport
diffusion, turbulence, convection, advection
diffusion (molecular)
random movement of gas molecules from a high concentration to lower concentrations that can take hours/days to move several meters
turbulent diffusion
random macroscopic swirls of air that move much faster than molecular diffusion
relation between pollutant residence time and distance traveled
longer residence time means the farther the pollutant con potentially travel
what is brownian motion
random direction changes resulting from collision
what is a turbulent eddy
random swirls of air from millimeters to many meters in diameter
advection, what it is and the pace
horizontal transport - wind spreads pollution at typical wind speeds, 10-20 km/hr and max of 400 km/hr
convection transport
vertical transport - warm air rises, cold air sinks and can transport pollutants to heights where winds are stronger
if density of gas parcel is greater than the density of the air it’s in…
the parcel is heavier and will sink because there is a negative buoyancy force
if density of gas parcel is less than the density of the air it’s in…
air parcel has less weight than the air so it rises; positive buoyancy force
if density of gas parcel is equal to the density of the air it’s in…
the parcel weighs the same as the air it’s displacing and vertical forces are in balance so it floats and is at neutral buoyancy
law of buoyancy
an object inside a fluid will rise as long as its density is smaller than the density of the fluid and vice versa
ideal gas law
P = kb x n x t (kb equals Boltzmann constant and n equals concentration)
boyles law and relationship to each other and density
p1v1 = p2v2 inverse to each other; pressure and desnity are directly proportional
charles law and relationship to each other and to density
t1/v1 = t2/v2 directly proportional to each other and inversely proportional to density
adiabatic expansion/compression
without loss or gain of heat; mechanical work takes or gives energy to air molecules, thus changing the temp without adding or losing heat
adiabatic expansion
gas cools down
adiabatic compression
gas heats up
why does air cool as it goes upwards
caused by a drop in pressure which causes the air to expand and the air molecules to have to provide the work for the expansion, taking energy away from the parcel
when does adiabatic expansion stop
until the pressure inside and outside are equal
dry adiabatic lapse rate (symbol and value)
drop 10c per 1 km altitude increase (uppercase gamma)
saturated adiabatic lapse rate (100% humidity)
drop 5c per 1 km increase
environmental lapse rate
lowercase gamma, can be anything because its the real atmosphere; called a sounding
what to call the adiabatic lapse rate line on the graph
adiabat
describe the santa ana wind process
air parcel start at high elevations in the desert and high pressure system forces the air from the dessert to the coast line over the mountains where it descends to sea level and has a net decrease in altitude and thus undergoes adiabatic compression where it gains temperature
how does an air parcel leave the ground in the first place
hot ground heats the air nearby where it becomes less dense and rises
what happens if the environmental lapse rate and the air parcels lapse rate converge
the parcel stops rising when the temps are equal
what happens if the environmental lapse rate and the air parcels lapse rate diverge
the parcel maintains a high temp and continue to rise
stable atmosphere
the system resists the disturbance and returns to its original condition
unstable atmosphere
system accelerates away from its original condition
neutral atmosphere
system neither returns to nor accelerates away from original condition and instead establishes a new state of equilibrium
what lapse rates make for neutral stability
the adiabatic lapse rate and environmental lapse rates are equal
what lapse rates make for unstable atmospheric stability
environmental lapse rate is greater than the adiabatic lapse rate
what lapse rates make for unstable atmospheric stability
environmental lapse rate is less than the adiabatic lapse rate
what is a temperature inversion and what does one do for stability?
when the temperature in the atmosphere increases with increasing altitude and are extremely stable
inversion types [3]
marine
radiation
subsidence
marine inversion (advection inversion)
cold air from over water floats in along a sea breeze and slides underneath the warmer coastal air (stable); common in spring and summer
radiation inversion
forms at night when ground cools by radiating IR and the air cools by conduction, but the air aloft does not cool as quickly; tend to be shallow and dissipate with sunrise
subsidence inversion
sinking air aloft compresses adiabatically and forms warm air over cooler air and is associated with high pressure systems
why are inversions important
suppress convection and inhibit vertical movement of air and pollutants; acts like a lid
chimney plume types
fanning, looping, cone shaped, fumigation, lofting
fanning plume
occurs when the environmental lapse rate is less than the adiabatic lapse rate (stable atmosphere) which suppresses vertical convection so plume is flat and spreads out and plume stays away from the ground
looping plume
occurs when the environmental lapse rate is greater than the adiabatic lapse rate (unstable atmosphere) so natural turbulence sends off individual parcels upwards and downwards
cone-shaped plume
environmental lapse rate = adiabatic lapse rate (neutral atmosphere) and spreads upwards and downwards equally
fumigation plume (inversion above stack)
pollution does not mix above inversion base and plume is pushed to ground and creates worst air quality
lofting plume (inversion at or below top of stack)
plume stays above inversion and creates good ground air quality
what is acid rain
when rain or fog drops absorb anthropogenic pollutants such as SO2 NO2 and turn into sulfuric and nitric acid respectively
what does london smog come from
coal fires heating homes and factories combined with fog
3 things that played a major role in the formation of london smog
low inversions, emissions of SO2 and soot, and fog
what is an acid?
molecules that dissociate into negative ions and H+ ions in water e.g. vinegar and lemon juice
what is a base?
compounds that dissociate into positive ions and OH- ions in water; taste bitter, e.g. baking soda
equilibrium concentration of water
[H+] = [OH-] = 1E-7 mol/liter
what is a buffer?
a solution where H+ or OH- ions that are added will be removed, thus resisting a change in pH (weak acid and it’s base, or weak base and it’s acid)
what are free radicals
molecules with a free electron and are chemically very reactive
formation of sulfuric acid in the gas phase
SO2 + OH + O2 + H2O –>… mechanism… –> H2SO4 + HO2
sulfuric acid formation in water
gas gets dissolluted into water and then gets hydrated SO2 aq –> H2SO3
H2SO3 –> 2H+ + HO4 + H2O
natural sources and sinks of sulfur
sources: volcanoes and emissions from the land and oceans
sink: rainout into soil and ocean
how have humans contributed to sulfur emissions
by burning coal and oil
nitric acid formation in the gas phase
NO2 + OH –> HNO3
HNO3g –> HNO3 aq –> H+ + NO3-
where do NO and NO2 come from naturally
lightning and soil
where do NO and NO2 come from now?
combustion
sources of NOx in US
on road vehicles, construction machines, electrical generators
where are the highest levels of NOx found?
urban centrals
bases in the atmosphere
ammonia from cattle waste and landfills and lime
what is wet deposition
acids and other gases are taken up by water droplets which are deposited when acidic clouds come in contact with mountains or fog on the ground with plants
what is dry deposition
acids and other molecules taken up by surfaces
acid rains effects
damages forests; lake acidification or alteration of ecosystems; destruction of art or infrastructure; human health effects
how to combat acid rain
scrubbers to reduce emissions and low sulfur fuels and alternative energy sources
how to most effectively implement emission reductions
cap and trade system
most effective smog reducer in LA
catalytic converters on cars
pollutants that characterize LA smog
primary pollutants - NO/NO2, CO, hydrocarbons
secondary - ozone/particulates, NOx
what is a primary pollutant
pollutant that is directly emitted
what is a secondary pollutant
pollutant that is formed chemically from exposure of primaries to sunlight or other sources
temps with most smog in LA vs London
LA - warm
London - cool
inversions that enhance pollution in LA vs London
LA - subsidence and marine
london - radiation
time of pollutant peak in LA vs London
London - morning
LA - afternoon
what emits carbon monoxide
combustion processes under oxygen poor conditions like fat burning engine
residence time of CO
days-weeks
sources of NOx
lighting, biomass burning, soil bacteria, fossil fuel combustion (dominant)
residence time of NOx
1-3 days
sources of hydrocarbons
plants, solvents, fuel fumes, unburned fuel
sources of particles in LA smog
direct emissions from things like diesel exhaust and smoke stacks
how to measure visisbility
L of visibility (km) = 1000 / TSP
how does inversion height in LA vary throughout the day
lower at night and morning and higher in the afternoon due to solar surface heating
how does inversion height in La vary by season
lower in winter because of cooler temperatures and higher in the summer because of higher temperatures
land-sea breeze day/night
by day the cool ocean air gets blown onshore and heats up and rises so more ocean air comes to the coast but at night the land air moves to the ocean because the land cools faster
what are the national primary ambient air standards
levels of air quality which the EPA judges are necesarry with an adequate margin of safety to protect public health
national secondary ambient air standards
levels of air quality which the epa judges are necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant
why so difficult to combat smog in LA?
the ridge down the middle of the graph of NOx vs HC emissions and ozone
strategies to reduce smog in LA
move industry/power plants out of the basin
regulate and control industrial emissions
regular compliance controls of emitters
prescribing lower emission standards for cars
challenges for the future of LA smog
urban sprawl and increasing populations
percent of time spent indoors
87% (even in good weather)
where do indoor air pollutants come from?
infiltration from outdoors (negligible); insulation/radon seepage; combustion sources; building materials and furnishings; household cleaners; personal care products; heating/cooling systems
where does formaldehyde come from?
latex paint/new carpet; outgassed from objects with resins or plastics (dye stabilizer); engineered wood products; foam insulation (banned); combustion (cigarettes); textiles; glues and foams
standard health effects of formaldehyde in a newly constructed home?
cerebral cortex affected
why do people smoke
nicotine - stimulant and depressant - calmer yet more alert - addictive
health effects of smoking
CO reduces blood oxygen level; carcinogenic; premature aging
mainstream smoke
smoke that comes directly from the cigarette (tobacco burns hot so theres less CO being actually inhaled)
sidestream smoke
smoke that comes from smoldering between puffs; burns at a lower temp so more CO and other pollutants
environmental tobacco smoke (ETS)
diluted side stream smoke, exhaled mainstream smoke; low concentration but not negligible
tobacco smoke constituents
tar, nicotine, CO; formaldehyde; phenols; toluene
health effects of tobacco smoke in the mouth/nose/throat
cancer in mouth, tongue, sinus, larynx; loss of taste and smell
health effects of pulmonary tract
lung cancer, coughing, asthma attacks
health effects on cardiovascular tract
restricted blood supply to internal organs => coronary, pulmonary heart disease, congestive heart failure, strokes
ingredients of “vapes”
heated mixture of polyethylene glycol (glycerin) and nicotine plus flavoring
what can one do about indoor air pollution
control sources and emissions, improve ventilation, air cleaners
where is indoor air pollution most commonly a problem and why
3rd world countries because of open fires burning indoors with poor ventilation
how to mitigate radon
sub-slab suction; seal foundation cracks
problems with air cleaners
hard to distinguish between good air and bad air; expensive; may not work for a long time; may not be able to filter out everything
how many rooms does a filter need to be able to pass through
6 times the volume of the room
